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 * The Universal Permissive License (UPL), Version 1.0
 *
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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
 * one is included with the Software each a "Larger Work" to which the Software
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 * without restriction, including without limitation the rights to copy, create
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
 * either these or other terms.
 *
 * This license is subject to the following condition:
 *
 * The above copyright notice and either this complete permission notice or at a
 * minimum a reference to the UPL must be included in all copies or substantial
 * portions of the Software.
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package com.oracle.truffle.jx.nodes;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.instrumentation.*;
import com.oracle.truffle.api.nodes.Node;
import com.oracle.truffle.api.nodes.NodeInfo;
import com.oracle.truffle.api.nodes.RootNode;
import com.oracle.truffle.api.source.Source;
import com.oracle.truffle.api.source.SourceSection;
import com.oracle.truffle.jx.nodes.local.SLScopedNode;

/**
 * The base class of all Truffle nodes for SL. All nodes (even expressions) can be used as
 * statements, i.e., without returning a value. The {@link VirtualFrame} provides access to the
 * local variables.
 */
@NodeInfo(language = "SL", description = "The abstract base node for all SL statements")
@GenerateWrapper
public abstract class JXStatementNode extends SLScopedNode implements InstrumentableNode {

  private static final int NO_SOURCE = -1;
  private static final int UNAVAILABLE_SOURCE = -2;

  private int sourceCharIndex = NO_SOURCE;
  private int sourceLength;

  private boolean hasStatementTag;
  private boolean hasRootTag;

  /*
   * The creation of source section can be implemented lazily by looking up the root node source
   * and then creating the source section object using the indices stored in the node. This avoids
   * the eager creation of source section objects during parsing and creates them only when they
   * are needed. Alternatively, if the language uses source sections to implement language
   * semantics, then it might be more efficient to eagerly create source sections and store it in
   * the AST.
   *
   * For more details see {@link InstrumentableNode}.
   */
  @Override
  @TruffleBoundary
  public final SourceSection getSourceSection() {
    if (sourceCharIndex == NO_SOURCE) {
      // AST node without source
      return null;
    }
    RootNode rootNode = getRootNode();
    if (rootNode == null) {
      // not yet adopted yet
      return null;
    }
    SourceSection rootSourceSection = rootNode.getSourceSection();
    if (rootSourceSection == null) {
      return null;
    }
    Source source = rootSourceSection.getSource();
    if (sourceCharIndex == UNAVAILABLE_SOURCE) {
      if (hasRootTag && !rootSourceSection.isAvailable()) {
        return rootSourceSection;
      } else {
        return source.createUnavailableSection();
      }
    } else {
      return source.createSection(sourceCharIndex, sourceLength);
    }
  }

  public final boolean hasSource() {
    return sourceCharIndex != NO_SOURCE;
  }

  public final boolean isInstrumentable() {
    return hasSource();
  }

  public final int getSourceCharIndex() {
    return sourceCharIndex;
  }

  public final int getSourceEndIndex() {
    return sourceCharIndex + sourceLength;
  }

  public final int getSourceLength() {
    return sourceLength;
  }

  // invoked by the parser to set the source
  public final void setSourceSection(int charIndex, int length) {
    assert sourceCharIndex == NO_SOURCE : "source must only be set once";
    if (charIndex < 0) {
      throw new IllegalArgumentException("charIndex < 0");
    } else if (length < 0) {
      throw new IllegalArgumentException("length < 0");
    }
    this.sourceCharIndex = charIndex;
    this.sourceLength = length;
  }

  public final void setUnavailableSourceSection() {
    assert sourceCharIndex == NO_SOURCE : "source must only be set once";
    this.sourceCharIndex = UNAVAILABLE_SOURCE;
  }

  public boolean hasTag(Class<? extends Tag> tag) {
    if (tag == StandardTags.StatementTag.class) {
      return hasStatementTag;
    } else if (tag == StandardTags.RootTag.class || tag == StandardTags.RootBodyTag.class) {
      return hasRootTag;
    }
    return false;
  }

  public WrapperNode createWrapper(ProbeNode probe) {
    return new JXStatementNodeWrapper(this, probe);
  }

  /** Execute this node as as statement, where no return value is necessary. */
  public abstract void executeVoid(VirtualFrame frame);

  /** Marks this node as being a {@link StandardTags.StatementTag} for instrumentation purposes. */
  public final void addStatementTag() {
    hasStatementTag = true;
  }

  /**
   * Marks this node as being a {@link StandardTags.RootTag} and {@link StandardTags.RootBodyTag}
   * for instrumentation purposes.
   */
  public final void addRootTag() {
    hasRootTag = true;
  }

  @Override
  public String toString() {
    return formatSourceSection(this);
  }

  /**
   * Formats a source section of a node in human readable form. If no source section could be found
   * it looks up the parent hierarchy until it finds a source section. Nodes where this was required
   * append a <code>'~'</code> at the end.
   *
   * @param node the node to format.
   * @return a formatted source section string
   */
  public static String formatSourceSection(Node node) {
    if (node == null) {
      return "<unknown>";
    }
    SourceSection section = node.getSourceSection();
    boolean estimated = false;
    if (section == null) {
      section = node.getEncapsulatingSourceSection();
      estimated = true;
    }

    if (section == null || section.getSource() == null) {
      return "<unknown source>";
    } else {
      String sourceName = section.getSource().getName();
      int startLine = section.getStartLine();
      return String.format("%s:%d%s", sourceName, startLine, estimated ? "~" : "");
    }
  }
}
